A variety of iatrogenic causes of cancer were explored, with major emphasis on the effects of oral contraceptives and menopausal hormones. Oral contraceptives were found to predispose to early-onset breast cancers, particularly among thin women and those with high levels of alcohol consumption. In a record-linkage study in Sweden, menopausal estrogen use was found to lead to reduced mortality for 12 major causes of death. Specific analyses considered type of estrogen and whether it was used with a progestin. An editorial was also prepared which weighed hormone-related risks of breast cancer against benefits for other diseases, including cardiovascular disease and osteoporosis. In a large follow up study, oral contraceptives and menopausal hormones were not found to be related to colorectal cancer risk. Other medical devices were also evaluated in relation to several cancer sites. Use of intrauterine devices, particularly inert ones, appeared to reduce the risk of endometrial cancer. Nearing completion is a large follow up study of a large number of women having received augmentation mammoplasties to assess the long-term health effects of exposure to silicone. In preparation for assessing cancer risks, a review of available literature on the topic was completed. A similar retrospective study of women evaluated and treated for infertility is underway. Of particular interest will be the risk of ovarian cancer related to ovulation stimulating drugs and of hormonally-related cancers following different types of infertility, including those due to hormonal problems. Cancer risk has also been evaluated in relation to different types of operations and diseases. Women undergoing bilateral oophorectomies at young ages were found to have low risks of subsequent breast cancer, while those with tonsillectomies, particularly at young ages, were at a high risk of Hodgkin's disease. Primary hemochromatosis was found to be a significant risk factor for subsequent liver cancer.